Ferromagnetic alloy



am Apr- 5.1938

:5.112.911 ramouaounnc 'suny Hans Neumann. Berlin-Siemenntadt. assigner to Siemens Halske, `Aktiengesell- UNITED- STATI-:sl .PATENTOFFICE fschaft, Siemensstadt, near corporation of Germany October 20,- 1934, Serial situation' m My invention relates to ferromagnetic alloys containing principallyiron, nickel and copper. As to the nature-of -such alloys it is well known that certain compositions are characterized 'by a iigh permeability.. others by a' small coercive orce. v According to the-present invention permeable ferromagnetic alloys containing as essential constituents iron, nickel and copper are so chosen that the 'composition as to the content of the three above-mentioned constituents lies within a deiiv nite range, characterized in the accompanyingcomposition diagram by the hatched area. In this case the. nal, quarternary alloy must.` besides, contain still an amount of molybdenum than 1 per cent. but not more than i0 percent. Thus, 'in all cases the ilnal product is a quaternary alloy. As will be apparent from the diagram of the drawing in thecase of alloys containing molybdenum ternary master alloys are employed whichcontain at most per cent iron, at most55 per cent copper and 40 to 90 per cent nickel. Y With. alloys thus composed not only is it po'ssible to attain'particularly high initial permeabilities, but also the alloys have at the same time the advantage that the maximum permeability coincides with the minimum coercive force.

. Itis well known in the art to add molybdenum4 to ferromagnetic alloys. Thus, for instance, a

small amount of molybdenum has been hitherto added to n-nickel alloys so as to increase the speciilc ce. However, in` these alloys the initial permea denum content. Further,y the value ofthe coercive force remains relatively high, i. e.,`thevalues obtained are allV greater than H=.035 Oersted.

` If an amount of molybdenum of not less. than 1 and not more than l0 per cent is, however, 40 copper alloys containing 40 to 90 p'er cent nickel` and 'not more than 25 per cent iron with not more than peil cent copper, considerably higher .initial permeabilities and smaller coercive forces may be attained. i ,A Favorable results are obtained, if-the composition of the alloys is so chosen that the composition as to itsk iron, nickelcopper content lies within the hatched range vas shown in the ac- 50 In-this diagram for the Fe element content the abscissa is represented 'by the line (2u- NL and the ordinate by the line i Cul"e:fortheNi content the. line is Per-Cu, the ordinate line IMA-Ni, and for the m;cu eoz n=entuw auiciasaline:nu-11e.anocheY Germany October 24. 1 983 fromm. (cL' iss-s1) ty is not increased by the molybadded according to the invention to iroxi-nickelthan the optimum .values hitherto attained inA a Berlin, Germany, a A

N. 'naiss ordinate line Ni--Cu.A In allcaseswhere in this shaded area the constituents o! the ternary masf ter alloy\ supplement one another to 10095, -the content of at least one ofthe constituents is assumed to be reduced -vpcrcentually to the 5 extent to which molybdenum is added, so that` the content percentages of the n nal. quaternary .1'

alloy total up Thun-for irutancain an alloy lying within this range containing 'l0 initialpermeability uia=l8,0u0 may be ed. However, if acomposition ofv'l per' Del'. att

'.cent nickel, l0 'per cent iron, 1'l 'per cent copper to the invention the value of time initial permea- 1g ities. of more than 40,00'0 have been obtained, the

coercive force being at the same time reduced.- More cxact values are indicated, in the following table which shows a comparison o! iron-nickely copper alloys without; and with Percentlgeof n. oil-mug any ferromagnetic alloys be ibtained alloys according to the inventiirm.l Buch low'values "have been hitherto only obtained with pureiron in the' research laboratory. However, it was not'L possible tov utilise these 'favorable values m cchnlcallmsinceitisdimculttopmduceimn of suilicient purity in great quantities economically. Turthermorait'isprscticallyimpossible to iron pure, when subieetingit to thetreatment production u' cent nickel, 13 per cent-iron and/17 per cent cop-"10 Y -duction of magnetic bodies is simplified but it and treatment of ferromagnetic alloys according to the invention present no diiliculties. Furthermore, also the value of the specic resistance simultaneously attained with 'the low coercive force is considerably greater and, therefore, more favorable than in the case of pure iron.

As a result oi the small coercive force the material according to the invention becomes extremely important. for instance, for the manufacture of relays which owing to the great reduction oi the interfering coercive force may be considerably slmpliiled. The manufacture of magnetic bodies may also be greatly improved owing to the following circumstance: In ironnickel-copper alloys free of molybdenum the maximum initial permeability is obtained by cooling the alloys suddenly from a higher temperature. The addition of molybdenum has the effect that the favorable magnetic properties are obtained by a gradual cooling. 'I'he material is, for instance, kept for 5 to 10 hours at an annealing temperature of about l100 C. and then it is gradually cooled in the furnace. By avoiding ay sudden cooling of the material not only the proalso eliminates the danger that stresses due to chilling may occur in the body which impair its magnetica] properties.'

The addition of molybdenum has'not only the effect of increasing the permeability of the alloy,

but also'the specific resistance as is apparent from the above table.

I claim as my invention: I

l. A highly permeable ferromagnetic alloy consisting of 72% Ni, 14% Cu, 11% Fe and 3% Mo.

2. A highly permeable ferromagnetic alloy consisting of 70% Ni. 17% Qu. 10% Fe and 3% Mo.

3. A highly permeable ferromagnetic alloy consisting of 'l0-'14% Ni. about 1012,% Fe, 24% Mo and the restcopper.

4. A highly permeable ferromagnetic material consisting of 'l0-74% Ni, about lil-12% Fe, 24% Mo and the rest copper, and having an enhanced initial permeability obtained by annealing at 600 to 1101)'I C. and thengradually (cooling the material.

HANS NEUMANN. 

